<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    let cxk = {
      name: '鸡你太美',
      gender: '未知',
      song: function () {
        return 'wait wait wait'
      }
    }
    for (let key in cxk) {
      console.log(key)
      // document.write(cxk[key])  // cxk[name]
    }                             // cxk.name
                                 // cxk['name']
  </script>
</body>

</html>